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VALVE APPARATUS FOR VACUUM RAILWAY BRAKES.

Patented Nov. 26, 1889.

INVENTOH.

W/TNESSES.

(No'Model.) 2 Sheets-Sheet 2.

J. GRESHAM.

VALVE APPARATUS FOR VACUUM RAILWAY BRAKES.

No. 415,968. Patented Nov. 26, 1889.

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UNITED STATES PATENT OFFICE.

JAMES GRESHAM, OF MANCHESTER, COUNTY OF LANCASTER, ASSIGNOR TO THE VACUUM BRAKE COMPANY, (LIMITED,) OF LONDON, ENGLAND.

VALVE APPARATUS FOR VACUUM RAILWAY-BRAKES.

SPECIFICATION forming part of Letters Patent No. 415,968, dated November 426, 1889.

Application filed January 8, 1889. Serial No. 295,535. (No model.) Patented in England April 28, 1888, No. 6,320.

T all whom it may concern.'

Be it known that l, JAMES GRESHAM, a subject of the Queen of Great Britain and Ireland, of the firm of Gresham & Craven, engineers and machinists, of Craven Iron Works,

Salford, Manchester, in the county of Lancaster, England, have invented new and useful Valve Apparatus for Vacuum Railway Brakes, (for which Letters Patent have been 1o applied forin Great Britain, to bear date April 28, 1888, No. (i,320,) of which the following is a speciiication.

This invention relates t0 valve apparatus applicable for use with automatic brake-cylinders and vacuu 11n-chambers, the same being specially adapted for use with trains composed ot' a great number of vehicles, the object being to enable the brakes to be applied in cases of emergency throughout the train with greater rapidity than is attainable when the air is admitted through the train-pipe alone to the brake-cylinders.

Vith vacuum automatic brake apparatus as ordinarily constructed for applying the brakes air is admitted through one opening, controlled by a valve or otherwise, to the train-pipe, and thus to the brake-cylinders of several vehicles. For ordinary sto ppages and with trains of average length the brakes are thus applied with suiticient rapidity and the train is retarded or arrested without shock. For expediting the application of the brakes valves for admitting air to the train-pipe are usually placed in the guards vans, these valves being contrived so as to act automatically when air is suddenly admitted to the train-pipe by way of the drivers valve or in consequence o'f the couplings becoming disconnected or broken. y One'object of the present invention is to provide means whereby air may be admitted directly-that is, without passing through the brake-pipemto the brake-cylinder of each. vehicle, the brakes being thereby brought into action with greater rapidity and almost simultaneously throughout a train of any length.

In order that my improvements may be Figure 1 is a vertical section of a brakecylinder, showing the application of my invention thereto, Figs. 2 and 3 being vertical sections, drawn to an enlarged scale, of my improved valve mechanism.

Similar letters of reference are employed in all the figures to indicate corresponding parts so far as they appear.

a is thevacuum-chamber, provided with 6o trunnions d.

a2 is the brakecylinder, arranged within the chamber a.

a3 is the piston, furnished with a rolling packing-ring a4 and a piston-rod a5, to which 65 the lever for actuating the brake rods and blocks is connected.

The parts above referred to by referenceletters are ordinary and well-known parts appertaining to vacuum-brake apparatus.

To the under side of the brake cylinder or chamber a is secured a casting b, in which are formed passages h and h2, the former leading from the train-pipe to the under side` of the piston a3 (or diaphragm, when used) 75 and the latter leading from a side branch from the passage b past a ball-valve to the vacuum-chamber and to the upper side of the piston a3. The ball-valve is mounted in a tubular carrier b3, which at one end lits and 8o slides upon a tubularprojection formed upon the casting b, the extremity thereof serving as a seating for the ball-valve h4 when in the position shown in Fig. 2. The other end of the valve-carrier b3 is enlarged and has lat- 85 eral orifices for the admission of air from the surrounding chamber, and to the enlarged end of the carrier b3 is attached a stem b5, which secures the middle part of a diaphragm h6 air-tight between the end of the tube b3 9o and a collar formed upon the stem b5. The outer edge of the diaphragm b is secured airtight between the face of a body 127 and the bottom of a recess formed in the casting h, wherein the part t7 is screwed. The part b7 95 forms a guide for the outer end of the stem h5, the latter being forked for the reception of a leverbs. (Shown in cross-section.) In Fig.

2 this lever is shown in dotted lines in elevation at right angles to its correct position. roo The movement of the lever bs in either direction withdraws the ball-valve b4 from its seat when it is required to admit air to the vacutim-chamber.

The above-described method of constructing and operating ball-valve mechanism resembles that described in the specification to Letters Patent of the United States numbered 332,653, and dated December 15, 1885, but is referred to in order that my present improvements may be more readily understood.

To the casting l) another casting c is attached, and between the flanges or adjacent faces thereof the outer edge of a diaphragm c', of india-rubber or other suitable iexible material, is secured air-tight. The middle portion of the diaphragm c is fastened between a shoulder formed upon the hollow body c2, andthe face of a ring or ferrule c3, which is screwed upon the neck of the same. The lower part of the hollow body c2 is enlarged and terminates in a flange whereof the face is recessed for the reception of a washer c4, composed of india-rubber or other suitable elastic packing material. To the interior of the enlarged part of the hollow body c2 is screwed a bush c5, the latter being formed with an outwardly-projecting ange, which assists in holding the washer c in position.

The casting c is formed with a seating c, against which the elastic packing c4 rests when the hollow body c2 occupies the position indicated in Fig. 2. Vithin the enlarged or lower portion of the hollow body c2 is arranged a ball-valve c7, which rests, when in its normal position, on cross-bars cs, formed in the casting c. Carried by cross-bars on the casting b is a pendent projection c,which extends into the neck of the hollow body c2. The side of the casting c is provided with numerous small holes om for the admission of the external air to the exterior of the hollow body c2 and to one side of the diaphragm c. The casting c is further provided with a branch c, to which a flexible tube communieating with the train-pipe is connected. Then a partial vacuum is formed in thetrainpipe, the atmospheric pressure upon the exterior of the hollow body1 c2 being greater than that upon the under side of the diaphragm c', the body c2 is maintained with its lower face resting upon the seat c, this position being also maintained when air is admitted to the train-pipe for ordinary applications of the brakes. The weight of the hollow body c2 also insures its remaining upon its seating c6 when the atmospheric pressures respectively inside it and outside it are equal. If, however, air be suddenly admitted to the train-pipe and in full quantity, as in a case of emergency or the severance of the train-pipe,

upon the lower side of the diaphragm c', operates to lift the body c2 from its seat c6 and to permit the external air to pass directly both to the train-pipe and by way of the passage o to the brake-cylinder, where it acts upon the lower side of the piston to apply the brakes. It will be understood that after the Valve c7 and body c2 have been lifted, as above described, the valve c7 is unseated by means of the pendent projection c.

In a train provided with automatic admission-valves of the kind above described upon the admission-Valve nearest to the point at which air is admitted to the train-pipe opening an additional quantity of air is enabled to gain access to the train-pipe, and thus in turn to induce and expedite similar action on the part of all the other admission-valves. Then the brakes have been applied, the valve c7 and the body c2 resume their original positions, communication by way of the holes c10 being thus out off ready for a vacuum to be again created in the train-pipe.

Fig. 3 illustrates a modified or alternative method of construction. The parts of the casting b are substantially the same as those shown in Fig. 2, except that the projection e9 is dispensed with. There is a hollow body c2, furnished with an elastic facing c4, arranged and held as described with reference to Fig. 2, and provided internally with a ball-valve c7 and a seating above same. Instead, however, of the hollow body c2 being connected with a diaphragm c', it is provided with an elastic-packed face d, held between a shoulder on the neck of the body c2 and a washer d', the latter being secured by a nut d2. The elastic-packed face CZ works against a seating formed on a disk or ring d3, mounted in a recess in the casting c, as shown, the joint being rendered air-tight by means of an elastic packing placed between the adjacent faces of the castings b c. Then both the faces c4 and d rest upon their respective seating's, the body c2 forms a differential valve, and the pressure of the atmosphere, entering through the holes el", tends to keep same closed, the gravity of the body c2 having a similar effect when the pressures on the respective sides thereof are equal. In solne instances an annular channel d* is made in the under face of the metal of the lower valve above the elastic facing c4L andsinall holes are drilled to allow the' atmosphere to pass from the holes cw to this annular channel di. Under such circumstances the india-rubber facing c4 is pressed very slightly upward into the annular channel when the valves are down on their seatings, and the pressure of the external air, acting in the annular channel d* to press the elastic facing c4 upon its seating, insures the closing of both valves firmly upon their respective seatings when there is a partial vacuum in the train-pipe. The back of the lower valve is furnished with notched wings d6, which serve to guide the body c2 in the disk d3 and to limit the extent of its vertical motion.

IOO

IIO

`When a large admission of air is made to the train-pipe, the valve CT is lifted against its seating and the body c2 is raised until the extended portions of the wings d6 arrive against the under side of the disk d3, whereupon air is admitted directly from the external atmosphere past the lower valve to the train-pipe and between the wings d and past the upper valve to the brake-cylinder, where it acts upon the under side of the piston. When the brakes have been applied, the gravity of the body c2 causes it to resume its original position, as previously described with reference to Fig. 2.

lVhat I claim as my invention, and desire to secure by Letters Patent of the United States, is-

1. In vacuum automatic brake apparatus, the combination, with the brake-cylinder, of a differential valve c2, placed between the atmosphere and the brake-cylinder and trainpipe, and which remains inoperative during the ordinary working of the brakes, and a valve c7, placed between the brake-cylinder and the train-pipe and which remains open under the same conditions, the two valves jointly serving, when the brakes are to be suddenly applied, to permit direct communication between the atmosphere and the brakeeylinder and train-pipe.

In valve apparatus for admitting air directly to the brake-cylinder of an automatic vacuum-brake, the combination of a differential valve c2 with a ball or other valve c7, the valve c2 having a passage through which air is exhausted from or admitted to the brakecylinder during the ordinary Working of the brakes, the valve c7 serving to temporarily close such passage and enable the valve c2 to be opened when air is suddenly admitted to the train-pipe.

3. In valve apparatus for automatic vacuum-brakes, the combination of the main valve h4 with the supplementary valves c2 and c7, the valve Zrl enabling air to be simultaneously exhausted from the vacuum-chamber and brake-cylinder or separately admitted to one side of the brake-piston, the valves d2 and c7 serving to open direct communication between the atmosphere and the brake-cylinder and train-pipe when circumstances require an exceptionally rapid application of the brakes throughout the train.

JAMES GRESHAM. lVitnesses:

JoNAs CRAVEN,

Solicitor, lVfcmchester. JOSEPH WINSTANLEY,

His Clerk. 

